i dunno guy's for me its basic physics.
molecules such as water vapour, co2, methane etc. are called greenhouse gasses for a reason.
this is because they readily absorb IR radiation and then re-radiate it.
so if you apply heat to a body of say 02 and an identical body of co2.
the o2 will allow most of the heat to pass through it. the co2 molecules however will absorb and re-radiate the heat. thus the gas will get hotter at a rate greater than the body of gas containing o2.
please look at this video
BBC News - Newsnight - Kitchen experiment 'proves' science of global warming
its a basic school expermiment being carried out.
and it proves that co2 does increase the heat of a volume of gas.
and as everything in the earth is remaining constant the temperature will go up.
also its dangerous to say (and also shows a lack of deeper understanding)
"but the average global tempererature is staying the same"
global warming will effect different regions in different ways.
some will get warmer, some will get colder.
some will simply get wetter, others will get dryer.
and as the main producer of greenhouse gasses, how can in not be man made.?